Process for resin impregnating cellulosic fabrics



Patented Dec. 23, 1952 UNITED STATES iPAENT OFFICE PROCESS FOR RESINIMPREGNATING CELLULOSIC FABRICS Arnold L. Lippert and William P. Hall,Wilmington, DeL, assignors to Joseph Bancroft & Sons 00., Wilmington,Del., a corporation of This invention relates to the production of afinish on fabrics composed of cellulose and regenerated cellulose andmixtures thereof, and the primary object of the invention is to producea durable to Water finish which has the luster hereinafter described,which is crease, spot and soilresistant, in which the individuality ofthe fibers and yarns is retained and the flexibility and elasticity ofthe fibers increased whereby the hand and drape of the fabric issuperior to the original, in which the feel of the fabric is soft ormellow (not dry to the touch), in which the fabric breathes well(substantially retains its porosity), is resistant to fraying, and inwhich the fabric is stabilized against shrinkage, with substantialretention of the original tear strength.

As will be hereinafter set forth in detail, in the practice of ourinvention we employ a mechanical finishing machine and thermosettingresin-forming materials, which are applied in the water soluble stateand polymerized into the water insoluble state, by heat. Such materialsin relatively large concentrations have been employed to crease-prooffabrics, but the finished fabric has a dull or lack-luster appearance.Such resin-forming materials have also been used in combination withmechanical finishing to produce a fabric having a durable relativelyhighly glossy luster, such, for example, as a chintz fabric.

In the latter procedure, the finishing machine, whether a chasingcalender, a friction calender, a smooth or flat nip calender, aschreiner calender or an embossing calender, operates with relativelyhigh pressure, say, for example, a total pressure of 29 tons, 39 tons,49 tons, or even higher, in some cases. In each case certain of thebowls of the calender are ordinarily heated. Due to the heat somepolymerization of the resinforming material occurs in the machine. Dueto the pressure and the friction (which is intentionally present in thefri tion calender and unavoidably present to some extent in the othercalenders) on the fabric in passage of the fabric through the machine,the polymerized material on the fabric is caused to flow and is given apolishing action. This flowing and polishing is enhanced by the presenceof water, in which connection it is the custom to only partially dry thefabric before passage through the machine, the free moisture (about ormore over natural moisture content) in the fabric acting as aplasticizer of any polymerized material present. Due to the flowing andthe polishing action, surface deposits of polymerized material areironed into a continuous coating and are, as it were, shined up so thatthe resultant luster optically appears as a highly glossy surfaceluster. In the presence of such free moisture, which is also aplasticizer of cellulose, the pressure of the machine itself produces arelatively glossy finish luster which, as described, is enhanced by theflowing and polishing of surface deposits thereon. The fibers and yarnsof the fabric lose in individuality and therefore suffer a substantialreduction in their flexibility and elasticity so that the finishedproduct, after washing and drying, has been stiffened therefore has lostin hand and feel, and the crease-resistance is relatively low. Theflowing and polishing also tends to fill up or close interstices.

In the production of the finish of this invention we aim on the one handto avoid the dull lack-luster appearance obtained in crease-proofing,and on the other hand to avoid the loss in individuality, flexibilityand elasticity of the fibers and reduce the closing of intersticeshereinbefore described in connection with highly glossy finishes, whileobtaining a luster which optically appears as an interior deep-seatedluster or glow rather than a glossy surface luster and while obtainingquite substantial crease-resistance and the other properties of thefinish hereinbefore first described.

Generally speaking, in the practice of our invention we first prepare aWater solution of the resin-forming materials, containing, in the caseof cotton and the like, a permanent softener, and also containing adelayed action catalyst of the character to be hereinafter described,the resinforming materials constituting from 5% to 20% of the solutionby weight, with the softener constituting but a very minor part, from 1%to as high as 4% by weight of the solution, and with the catalystconstituting from 3% to 5% by weight of the solid resin-formingmaterial.

The solution is applied to the fabric in any well known Way as byimpregnation, spraying, or the like, with a solution pick-up fromapproximately to on the weight of the fabric in its natural dry state.The fabric is now dried by running it through an atmosphere heated tofrom substantially 200 F. to 350 F. for a period suificiently long toremove substantially all free moisture, and then cooled as by passingover cooling cans, leaving behind substantially only the naturalmoisture at room temperature. In other words, a cotton fabric has anatural moisture content of from substantially 4% to substantially 6%,and rayon from substantially 7% to 9%.

The fabric is now run through the mechanical finishing machine eitherone or more times.

In the case of melamine-formaldehyde, ureaformaldehyde anddicyandiamide-formaldehyde resins, the delayed action catalyst is of thetype which has a pH on the dried fabric of from substantially 6 pH tosubstantially 8 pH as determined by indicator solutions, but which willdevelop high acidity at the relatively elevated temperatures hereinafterto be more particularly pointed out in connection with thepolymerization of the resin-forming materials to the water insolublestate. In other words, the catalyst gives for all practical purposessubstantial neutrality or very low acidity on the fabric, when it has atemperature of substantially 212 F., which it will have for a fewseconds at the time the free moisture has just been driven off. 'Thecooling is to drop the temperature of the fabric quickly to roomtemperature or below (say from 60 F. to 100 F.) under which conditionsthe polymerization is kept at a negligible minimum. (Out of excessprecaution, one may also add ammonium hydroxide to the solution tomaintain neutrality during drying and until the am monia is driven off.)

The dried cooled fabric is now run through the finishing machine, whichis operated at such a temperature that the temperature of the fabricwill always be at or below 200 F., as will further appear. (We prefer arange of temperature of the fabric of from 100 F. to 175 F.) Bymaintaining the temperature of the fabric in its passage through theheated calender below 200 F., it will be seen that the catalyst willremain substantially neutral and the pH will not fall below 6 pH, atwhich pH the rate of polymerization will be so low that for allpractical purposes little polymerization can occur during passagethrough the calender.

After passage through the calender, the fabric is run through an oven inwhich the temperature and the time of residence are sufiicient- 1y highto cause the catalyst to develop marked acidity, say a pH of 4 or 5,whereupon the catalyst will catalyze the reaction and the resin-formingmaterial will be polymerized and become waterinsoluble. The fabric isnow washed to remove unreacted materials and dried, when it is in thefinished state.

It will be seen from the foregoing that at the time of the imparting ofthe mechanical finish there is little polymerization of theresin-forming material, the rate of polymerization being relativelyexceedingly slow under the conditions; and, no substantially polymerizedmaterial being present, the luster imparted is that which is obtainedessentially by the pressure and polishing action of the machine on thecellulose fibers and yarns themselves. In other words, the machinephysically deforms the fibers and yarns only to the extent that they canbe deformed by the machine. The luster imparted by the deformation andpolishing of the fibers and yarns is thus of subdued character due tothe absence of any appreciable free moisture or other plasticizer ofcellulose. Since polymerization of the resin materials to the insolublestate occurs subsequently and only at a time when there is no pressureon the fabric, there is no flowing or polishing of the resin formed, inconsequence of which the luster of the finished product, i. e., thewashed and dried fabric, is only that which is obtained in the finishingmachine on the fibers and yarns themselves, which luster is seen throughthe surface resin and appears not as a glossy surface luster but as aninterior or deep seated luster or glow. The fibers substantially retaintheir original individuality instead of being imbedded in a, hardbrittle resinous mass as in the case of regular highly glossy glazedchintz. This individuality, together with the increased flexibilitycaused by resin deposition, gives the finished fabric a hand, drape andflexibility superior to the original. The size of the interstices hasbeen to a large extent retained and the fabric has a good porosity whencompared with the original. The finished fabric has far morecrease-resistance than does durable chintz, for example, and has acrease-resistance approaching that obtained in the ordinary proceduresfollowed in producing crease-resistant fabric. The finish is durable torepeated washings and drycleanings and has the other propertieshereinbefore set forth. Since the hard resinous material produced in thepolymerization in the oven is formed when there is no pressure, thesoftener used in the case of cottons is now most effective to act, as itwere, as a lubricant whereby the original tear strength is substantiallyretained. In this respect the fact that the catalyst becomes activelyacid in the oven, also tends to the retention of tear strength. In thecase of regenerated cellulose a softener is not needed to retainstrength.

For thermosetting resin-forming materials we may employ anyacid-catalyzable materials, such, for example, as urea-formaldehyde,thioureaformaldehyde, dicyandiamide formaldehyde, mixtures thereof,melamine-formaldehyde, mixtures of melamine and urea or thioureadicyandiamide formaldehyde, and in fact any of the acid catalyzableresin-forming materials used in the textile art for producingcrease-resistance. For the formaldehyde, glyoxal may be substituted. Theresin-forming materials may be employed in the unreacted state or may bepartially condensed to the so-called A stage in which they are stillwater soluble.

For the catalyst we prefer to use carbazide hydrochloride. This may besubstituted by any of the following which are the equivalents for thecarrying out of the process, namely, phenyl biguanide hydrochloride;monoguanyl urea phosphate; di-monoethanolamine hydrogen phosphate;octadecyloxymethyl pyridinium chloride; and similar products such asCatalyst AC (an organic nitrogen chloride); and for the permanentsoftener when used we prefer to use octadecyloxymethyl pyridiniumchloride for which any of the following may be substituted asequivalents, namely, for the softener we may use the so-calledsubstantive cation active type such as Sapamine KW (trimethylammoniummethyl sulfate of monostearylmetaphenylene diamine) Triton K-60(tetra alkyl quaternary ammonium chloride), Ammonyx T (trialkylbenzylammonium chloride), and numerous other similar products sold under suchcommercial names as Soromine, a quaternary derivative of a cotton bowls,the steel bowls are heated to a temperature of from substantially 250 to300 F. In such a calender, 15 tons pressure is applied to each. ram.Calculated on the linear basis, with .bowls 60""wide, the. pressure isonehalf ton per inch ona 60" fabric.

The fabric is given 'a number of passes, preferably "four,

through each'nip'of the 5-bowl calender, i. e.,

there will be four thicknesses or layers of the fabric in the nipbetween each pair of bowls at all times. Underthese conditionsthetemperature of the fabric will remain well below 175 F. The number ofpasses may beincre'ased or decreased, so long asthe temperature achievedby the fabric is not above 175 F.

After the chasing calender the fabric is run through an oven having anatmosphere heated to a temperature of from substantially 250 F. tosubstantially 350 F. The timein the oven is from substantially 8 minutesto substantially 2 minutes. In the oven the resin-forming materials areipolymerized and become "water insoluble.

In the case of "a plain or flat nip calender, with howls rotating at thesame peripheral speed, the heated bowls may be safelyheated to-atemperature from 250 F. to 350-F., at-customary operating speeds whichare usually in the neighborhood of 150 yards per minute. These calendersare usually of the multi-bowl type having from three to seven bowls,although two-bowl'and nine-bowl machines are known. Where there are, forexample, seven or more bowls, the fabric is desirably run through onlyonce, with the temperature of the heated bowlssu ch as 'to ensure thatthe fabric does not achieve a temperature in excess of 175 F. Where thenumber of passes is smaller, the fabric -may be run-through two or threetimes, providing again that'the temperature of the heated bowls isnot-sufiicient to cause the fabric'to achieve a temperature above 175 F.

In the case of a schreiner or an embosser, the fabric can of course beonly run through once. Here a temperature on the-heated-bowl'may berelatively somewhat higherQbut'in no case should be such as to cause thefabric to "achieves temperature of substantially bove 175 F. In suchmachines a temperature ashigh as 350 F. may

be safely employed at customary operating speeds, which are usually inthe neighborhood of 15 yards per minute.

In the case of the 'frictionaglazer, thefabric is passedthroughthenipbut onceor twiceinstead'of the three or more times employedin the production of durable-Chintz. :The heated bowl in thiscase may beoperated at a'temperature of from substantially 300 :F. to'substantially350 F. at the customaryspeedsof operation, which areusually in'theneighborhood of 30 yards per minute. In this case a lubricant isdesirably present in the solution. The softeners heretofore listed arealso lubricants so they may be used in the double capacity in the caseof cottons. In the case of rayon, they act as lubricants. In the lattercase, non-permanent softeners or lubricantscanbe used, such assulfonated castor oil, sulfonated hydrocarbon (Avitone A) andpolymerized ethylene oxide (carbowaxes) may be used, and thismaterialis'largely "removed during the final washing.

Example I Solid resin 5% Cotton Chasehigh pressure-low temperatureCure-short time-hi'ghtemperature Dry--high temperature 40.0 lbs. AerotexM-3 (dimethyltrimethyl melamine-formaldehyde solid resin) 20.0 lbs.Aerotex #450 (dimethylol ureaformaldehyde resin 50% solid) 10.0 lbs.Iriton K-60 410 lbs. monoguanyl-urea phosphate -1 .0 lbpammoniumhydroxide (28%) 'to neu- -tralize -Water :to make *gallons.

A cotton fabric was impregnated with the above solution and squeezeduntil a' solutionpick-upof 7 0% was obtained.

This cloth wasthen dried in-an atmosphere of 350 F. until-approximately-6% moisture (nat ural) remained in the fabric which wasthen quickly'cooled to room temperature substan- The fabric was thenchase calendered in a 5-bowl machine using 50 ton total pressure and 250F. on the steel bowls. The speed of the machine was 170 yards a minute.

The fabric was then cured in an oven for 2 minutes at 350 F. and finallywashed and'dried.

The resulting fabric 'h'ada deep-seatedmellow glow' and'a soft drapery'hand-andwas more resistant to creasing than the original fabric.

'ErampZe 'II Solid content high 20% Rayon Chaselow pressure-hightemperature Curelong time-low temperature Dry-40w temperature 450.0 lbs.methylol urea-formaldehyde resin 20.0 lbs. Aerotex #801 (dimethylolureaformaldehyde'resin 100% solid) "2510* lbs. Sapamine K. W.

20.0 lbs. catalyst 'A. C.

1.0 lb. ammonium hydroxide (28%) *to neu- 'tralize Water to makegallons.

A spun rayon fabric was impregnated with the above solution, squeezeduntil 80% by weight of the solution was retained by the fabric which wasthen dried in a drying unit operating-at a temperature of 250 F. untilapproximately a total of 8% moisture (natural) remained in the fabric.

It was then quickly cooled to-approximately*60 Example -I I I 1. Solid12 2. Cotton 3. Chasemedium pressuremedium temperature 4. Cure-mediumtimemedium temperature 5. Dry-medium temperature 100.0 lbs. Resloom I-IP(di and trimethylol melamine-formaldehyde resin) 30.0 lbs. Ahcovel G 8.0lbs. di-monoethanolamine hydrogen phosphate 1.0 lb. ammonium hydroxide(28%) to neutralize Water to make 100 gallons.

A cotton printed broadcloth fabric was impregnated with the abovesolution and squeezed to remove excess solution. It was then carefullydried in a tenter frame at 300 F. to natural moisture and then quicklycooled to substantially 70 F.

The fabric was then chase calendered by running it once through a -bowlcalender operating at 30 tons and 275 F. The cloth was then cured 5minutes at 300 F. and finally washed and dried.

A beautiful deep-seated lustrous flexible fabric was obtained withincreased crease-resistance and good strength.

Example IV 1. Rayon 2. Glaze 60.0 lbs. Aerotex M3 100.0 lbs. methylolurea-formaldehyde resin 20.0 lbs. Avitone A 8.0 lbs. carbazidehydrochloride 1.0 lb. ammonium hydroxide (28%) to neutralize Water tomak 100 gallons.

A spun dyed rayon fabric, 40", 46/40, 3.50 yds./lb., was impregnatedwith the above solution, squeezed, dried, and cooled as described inExample III.

This fabric was glazed once by passing it through the glazing calenderoperating at 40 tons, 325 F. temperature and a friction ratio of 2:1.

The resulting fabric was cured 6 minutes at 290 F. and then washed anddried.

The resulting fabric had a good deep-seated luster and a linen-likeflexible hand and good crease-resistance.

Ezrample V 80.0 lbs. Aerotex M-3 60.0 lbs. Aerotex #450 20.0 lbs.Avitone A 10.0 lbs. catalyst A. C.

1.0 lb. ammonium hydroxide (28%) to neutralize Water to make 100gallons.

A 45", 39/32, 2.25 yds./lb. spun rayon (75%) cotton (25%) wasimpregnated, squeezed, dried, and cooled as described in Example III.

The fabric was then run once through a 5-bowl chase calender at 40 tonspressure and 250 F., followed by curing 3 minutes at 275 F. This wasfollowed by washing and drying.

The resulting fabric had a linen-like hand and appearance. In additionthe fabric was very flexible and decidedly resistant to creasing.

Example VI 1. Solid 11% 2. Glaze-high pressurehigh high friction 80.0lbs. Aerotex M-3 50.0 lbs. dicyandiamide-formaldehyde resin (50 30.0lbs. Triton K-BO temperature 6.0 lbs. carbazide hydrochloride 1.0 lb.ammonium hydroxide (28%) to neutralize Water to make 100 gallons.

15 A printed, 39", 80/ 92, 3.50 yds./lb., cotton fabric was sized anddried and cooled in the previously described manner in Example III. Itwas then passed twice through a glazing calender at 50 ton totalpressure at a temperature of 350 F. and

with a friction ratio of 23:1.

The fabric was then cured, washed, and dried in the usual manner.

A deep-seated lustrous, flexible, ful1 fabric of good crease-resistancewas obtained.

25 Example VII 1. Solid high 20% 2. Rayon 3. Flat nip-high pressurelowtemperature 4. Curemedium 5. Dry

460.0 lbs. methylol urea-formaldehyde (50%) 20.0 lbs. Rhonite #313(dimethylol ureaformaldehyde resin 50%) 20.0 lbs. Glyoxal 20.0 lbs.catalyst A. C.

1.0 lb. ammonium hydroxide (28%) to new tralize Water to make 150gallons.

" A spun rayon fabric was impregnated and squeezed with the abovesolution and then carefully dried to natural moisture and cooled asdescribed in Example III.

This fabric was given one run through a regular 5-bow1 fiat nip calenderoperating at 40 tons and 250 F. followed by curing 5 minutes at 300 F.After washing and drying, a deep-seated 10W luster crease-resistantfabric of a good full hand r was obtained.

" Example VIII 1. Cotton 2. Schreiner 80.0 lbs. Aerotex M-3 60.0 lbs.Aerotex #450 10.0 lbs. Sapamine K. W.

10.0 lbs. catalyst A. C.

1.0 lb. ammonium hydroxide (28%) to neutralize Water to make 100gallons.

Example IX 1. Cotton 2. Embossing A plain weave dyed cotton fabric wastreated as described in Example VIII except that the fabric was passedthrough an embossing calender instead of the schreiner. The results werethe same, except that there was also an embossed effect.

We claim:

1. The process of finishing fabrics of cellulose and regeneratedcellulose and mixtures thereof which comprises impregnating the fabricwith an aqueous solution of water-soluble acid-catalyzable thermosettingtextile resins of the aldehyde type in concentration of fromsubstantially to substantially by weight of the solution and carbazidehydrochloride as a catalyst, in minor part by weight, with a solutionpick-up of from substantially 70% to substantially 90% by weight of thefabric in the dry state, drying the fabric at temperatures between about200 F. and about 350 F. until it is substantially devoid of freemoisture, the drying being at a temperature and for a time such that thepH of the dried fabric is not below 6 pH as determined by indicatorsolutions, promptly after such drying, cooling the fabric tosubstantially room temperature, passing the dried, cooled fabric througha pressure mechanical finishing calender heated to a temperature suchthat the fabric is heated to a temperature of between from substantially100 F. to substantially 200 F. in its passage therethrough, and passingthe fabric through an atmosphere heated to from substantially 250 F. tosubstantially 350 F. for a residence time of from substantially 8minutes at the lower temperature to substantially 2 minutes at thehigher temperature.

2. The process of finishing fabrics of cellulose and regeneratedcellulose and mixtures thereof which comprises impregnating the fabricwith an aqueous solution of water-soluble acid-catalyzab lethermosetting textile resins of the aldehyde type in concentration offrom substantially 5% to substantially 20% by weight of the solution,

10 ootadecyloxymethyl pyridinium chloride as a softener and carbazidehydrochloride as a catalyst, each in minor part by weight, with asolution pick-up of from substantially to substantially by weight on thefabric in the dry state, drying the fabric at temperatures from about200 F. to about 350 F. until it is substantially devoid of freemoisture, the drying being at a temperature and for a time such that thepH of the dried fabric is not below 6 pH as determined by indicatorsolutions, promptly after such drying, cooling the fabric substantiallyto room temperature, passing the dried, cooled fabric through a pressuremechanical finishing calender heated to a temperature such that thefabric is heated to a temperature of from substantially F. tosubstantially 200 F. in its passage therethrough, and passing the fabricthrough an atmosphere heated to from substantially 250 to substantially350 F. for a residence time of from substantially 8 minutes at the lowertemperature to substantially 2 minutes at the higher temperature.

ARNOLD L. LIPPERT. WILLIAM P. HALL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,049,217 Meunier July 28, 19362,050,156 Borghetty Aug. 4, 1936 2,121,005 Bener June 21, 1938 2,242,218Auer May 20, 1941 2,347,024 Beer Oct. 18, 1944 2,454,391 Jones Nov. 23,1948 OTHER REFERENCES Ellis, The Chemistry of Synthetic Resins, vol. 1,1935, page 315.

1. THE PROCESS OF FINISHING FABRICS OF CELLULOSE AND REGENERATEDCELLULOSE AND MIXTURES THEREOF WHICH COMPRISES INPREGNATING THE FABRICWITH AN AQUEOUS SOLUTION OF WATER-SOLUBLE ACID-CATALYZABLE THERMOSETTINGTEXTILE RESINS OF THE ALDEHYDE TYPE IN CONCENTRATION OF FROMSUBSTANTIALLY 5% TO SUBSTANTIALLY 20% BY WEIGHT OF THE SOLUTIONCARBAZIDE HYDROCHLORIDE AS A CATALYST, IN MINOR PART BY WEIGHT, WITH ASOLUTION PICK-UP OF FROM SUBSTANTIALLY 70% TO SUBSTANTIALLY 90 % BYWEIGHT OF THE FABRIC IN THE DRY STATE, DRYING THE FABRIC AT TEMPERATURESBETWEEN ABOUT 200 F. AND ABOUT 350* F. UNTIL IT IS SUBSTANTIALLY DEVOIDOF FREE MOISTURE, THE DRYING BEING AT A TEMPERATURE AND FOR A TIME SUCHTHAT THE PH OF THE DRIED FABRIC IS NOT BELOW 6 PH AS DETERMINED BYINDICATOR SOLUTIONS, PROMPTLY AFTER SUCH DRYING, COOLING THE FABRIC SOSUBSTANTIALLY ROOM TEMPERATURE, PASSING THE DRIED, COOLED FABRIC THROUGHA PRESSURE MECHANICAL FINISHING CALENDER HEATED TO A TEMPERATURE SUCHTHAT THE FABRIC IS HEATED TO A TEMPERATURE OF BETWEEN FROM SUSTANIALLY100* F. TO SUBSTANTIALLY 200* F. IN ITS PASSAGE THERETHROUGHT, ANDPASSING THE FABRIC THROUGH AN ATMOSPHERE HEATED TO FROM SUBSTANTIALLY250* F. TO SUBSTANITALLY 350* F. FOR A RESIDENCY TIME FROM SUBSTANTIALLY8 MINUTES AT THE LOWER TEMPERATURE TO SUBSTANTIALLY 2 MINUTES AT THEHIGHER TEMPERATURE.